The pirate-inspired trend has been gaining ground for a while now, way before "Pirates Of The Carribean" was screened. Several months back, celebs were already donning Alexander McQueen scarves with the skull head motif, like Ashlee Simpson here :

There are more affordable alternatives, like this one :
Skull scarf $23 from girlshop.comAdmittedly, it's not a trend everyone will take to.
But for those who find it good fun, just remember not to go head to toe in skulls and cross bones !

Roses & Skull tank $19.50 from alloy.com
Vintage "Pirates rrrrrr cool !" Popeye tee $24.50 from alloy.com

Pirate Plasters $3.99 from drugstore.com
Skull rhinestone earrings $12 from fredflare.com

Pirate hobo $24 from amiciaccessories.com
URBAN DECAY eyeshadow palette $34 from sephora.com
Skull & Crossbones tank $9.99 from jcpenney.com